[wtp-releng] A note on DTP pre-req ... back to 1.5.1 for our M2

[David M Williams <david_williams@xxxxxxxxxx>]

Just to be explicit, 
once we get the I/S builds running again,
you'll notice that the pre-req for our M2 build will be DTP 1.5.1. 

I've learned that's what should be considered
their "M2". For a while they (and we) has a "1.6 M2",
but that should have just been "1.6 M3" so we should have not
moved to it (yet). 

I'm pretty sure this effects no one,
but thought I'd clarify, since it might otherwise appear we were "going
down" in version number of pre-req.